Upgrading Original IIe Motherboard

[tomk@pro-nsdapple.cts.com (Tom Kelly)]

I was testing some of my Apple IIe;s today
and noticed the following differences.
 
                Enhcaned IIe                            Original IIe
                820-0087-A                              820-0064-A
                607-0187-A                              607-0164-
                ----------                              ----------
X1              OPEN                                       CLOSED
X2              CLOSED                                     OPEN
X3              OPEN                                       N/A
X4              OPEN                                       OPEN
X5              CLOSED                                     CLOSED
X6              OPEN                                       OPEN
X7              OPEN                                       N/A
CHIP AT D1      HAL 341-0170-A                        PAL/HAL 342-0076A
 
The original IIe can not do DHR.
In fact the computer will not boot if I install the jumper block on the
80 col/64k card.
 
I have several questions about the original IIe.
1) Can it be enhanced with enhancement chip set (65c02, CD, EF, Video ROMs)?
2) Was the motherboard upgrade to support DHR FREE?
   If so, it still available?
3) How can I modify the motherboard myself to support DHR?
----
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